In the context of consumer electronics, a wearable device is a device that is worn by a user and that include smart electronics. Examples include smart watches, as well activity and health trackers that include bands that can be strapped to users' wrists like regular wristwatches. For instance, besides providing the ability to “tell time,” a smart watch may also link to a user's smartphone, and permit the user to answer, dismiss, and make phone calls, as well as display information to the user and receive limited input from the user. A user can thus use a smart watch as an extension of or accessory to his or her smartphone. A smart watch may also have activity or health tracking functionality like an activity or health tracker, tracking the number of steps a user takes, the user's heart rate, and so on. This collected information may be periodically transmitted from the smart watch to a user's smartphone, or to another device, such as over a network.